Process for making polyimide prepolymer with mixture of phenolic and hydrocarbon solvents

ABSTRACT

A method is provided for making a curable polymeric reaction product of an organic diamine and an aliphatically unsaturated dicarbonyl compound such as an organic anhydride or organic dicarboxylic acid. The curable polymeric reaction product can be heat softened to allow incorporation of filler and is convertible to the infusible state by heat or by the employment of a free radical initiator. Reaction of the organic diamine and the aliphatically unsaturated dicarbonyl compound is effected in a phenolic-liquid hydrocarbon solvent medium. The hydrocarbon can serve as an azeotroping agent to effect removal of water of reaction prior to the recovery of the reaction product of the organic diamine and the aliphatically unsaturated dicarbonyl compound. The polymeric reaction product can be molded to produce high temperature resistant polyimide films and structures.

United States Patent Holub et al.

[ 54] PROCESS FOR MAKING POLYIMIDE PREPOLYMER WITH MIXTURE OF PHENOLICAND HY DROCARBON SOLVENTS [72] Inventors: Fred F. Holub; John T. Hoback,both of Schenectady, N.Y.

[73] Assignee: General Electric Company [22] Filed: April 6, 1970 [21]App]. No.: 26,079

[52 US. Cl. ..260/78 UA, 204/ 159.22, 260/ 30.2, 260/3l.8 N, 260/32.6 N,260/33.4 R, 260/33.6 UA,

260/33.8 UA, 260/41 R, 260/47 UA, 260/47 CZ,

260/47 CP, 260/65, 260/78 TF, 260/827, 260/857 UN, 260/875, 260/897 B,260/899 [151 3,678,015 [451 July 18,1972

3,380,964 4/1968 Grundschober et a1 ..260/78 UA 3,406,148 10/1968Sambeth et al ..260/78 UA 3,533,996 10/1970 Grundschober et al ..260/78UA 71 ABSTRACT A method is provided for making a curable polymericreaction product of an organic diamine and an aliphatically unsaturateddicarbonyl compound such as an organic anhydride or organic dicarboxylicacid. The curable polymeric reaction product can be heat softened toallow incorporation of filler and is convertible to the infusible stateby heat or by the employment of a free radical initiator. Reaction ofthe organic diamine and the aliphatically unsaturated dicarbonylcompound is effected in a phenolic-liquid hydrocarbon solvent medium.The hydrocarbon can serve as an azeotroping agent to effect removal ofwater of reaction prior to the recovery of the reaction product of theorganic diamine and the aliphatically unsaturated dicarbonyl compound.The polymeric reaction product can be molded to produce high temperatureresistant polyimide films and structures.

6 Claims, No Drawings PROCESS FOR MAKING POLYIMIDE PREPOLYMER WITHMIXTURE OF PI-IENOLIC AND I-IYDROCARBON SOLVENTS The present inventionrelates to a method for effecting reaction between an organic diamineand an aliphatically unsaturated dicarbonyl compound, such as an organicanhydride, in a phenolic hydrocarbon solvent medium and to productsproduced thereby.

Prior to the present invention, mixtures of aliphatically unsaturatedorganic anhydrides, such a maleic anhydride and organic diamines weregenerally employed to make aliphatically unsaturated bisimides.Grundschober et al. U.S. Pat. No. 3,380,964 shows thatm-phenylene-bis-maleimide, can be converted to the infusible state attemperatures up to 400 C. Although the conversion of such bisimides tothe infusible state can provide cured products having valuableinsulating and dielectric properties, the cured products are generallyextremely brittle. In addition, these bisimides have sharp meltingpoints causing them to flow suddenly limiting their usefulness incommercial molding applications.

The present invention is based on a discovery that a mixture of organicdiamine and aliphatically unsaturated dicarbonyl compound, such as anorganic anhydride, or organic dicarboxylic acid, can be converted to apolyimide prepolymer having improved processibility in moldingapplications. The method involves forming a solution of organic diamineand aliphatically unsaturated dicarbonyl compound, in a phenolichydrocarbon solvent medium, and heating the solution to effect theseparation of an azeotrope of the hydrocarbon solvent and water ofreaction of the organic diamine and the unsaturated dicarbonyl compound.

There is provided by the present invention a method which comprises:

Lheating a mixture comprising (A) organic diamine, (B) aliphaticallyunsaturated dicarbonyl reactant selected from organic anhydrides andorganic dicarboxylic acids, (C)a hydrocarbon solvent, and (D) a phenolicsolvent,

2. separating a hydrocarbon solvent-water azeotrope from the mixture ofl and 3. recovering a curable polymeric product comprising the reactionproduct of (A) and (B) from the resulting mixture of l Some of theorganic diamines which can be employed in the practice of the inventionare compounds included by the formula,

where R is a diorgano radical, for example a heterocyclic radical, anarylene radical having from six to 15 carbon atoms and YGY, where Y isarylene, such as phenylene, toluene, anthrylene, arylenealkylene, suchas phenyleneethylene, etc., G is a divalent organo radical selected fromalkylene radicals having from one to carton atoms, O-, -S-, S0

2,4-bis(B-amino-t-butyl)toluene;

propylenediamine; hexamethylenediamine; heptamethylenediamine;otctamethylenediamine; nonamethylenediamine; decamethylenediamine;3-methylheptamethylenediamine; 4,4-dimethylheptamethylenediamine; 2,1l-diaminododecane; l,2-bis( 3- aminopropoxy)ethane;2,2-dimethylpropylenediamine; 3- methoxyhexamethylenediamine;2,5-dimethylhexamethylenediamine; S-methylnonamethylenediamine; l,4-diaminocyclohexane; 1,12-diaminooctadecane; 2,5-diamino-1,3,4-oxadiazole; H,N(CH O(CH O(CI-I NH,; flM HmStQHa-fit gH2N(CH2)3N(CH3) zh 2; and mixtures thereof; Organic amine mixturesconsisting essentially of the organic diamines of formula (I), andorganic monoamines such as arylamines, for example aniline,aminobiphenyl, etc.; aliphatic amines such as allylamines, etc., alsocan be employed as the organic diamine in the practice of the invention.

Included by the aliphatically unsaturated carbonyl compounds which canbe used in the practice of the invention are organic anhyrides, such asmaleic anhydride, citraconic anhydride and itaconic anhydride. Mixturesof such aliphatically unsaturated anhydrides and organic anhydrides suchas tetrahydrophthalic anhydrides and endomethylenetetrahydrophthalicanhydride, or Nadic" organic anhydride and methyl and halogen, forexample chloro derivatives of such anhydrides, etc. also can beemployed.

In addition to the above organic anhydrides, the aliphaticallyunsaturated carbonyl compounds also include aliphatically unsaturateddicarboxylic acids such as fumaric, maleic, 5-vinyl-isophthalic, etc.

Mixtures of such aliphatically unsaturated carbonyl compounds containingup to 10 mole percent of organic dianhydrides, for example pyromelliticdianhydride, 3,3',4,4'- benzophenone dianhydride, etc., based on thetotal moles of components in the anhydride mixture also can be employed.

In the practice of the invention, a mixture of the organic diamine asdefined above, and the aliphatically unsaturated carbonyl compound,which hereinafter can signify the aliphatically unsaturated anhydride,dicarboxylic acid or mixtures thereof is formed in aphenolic-hydrocarbon solvent medium. The term phenolic solvent asutilized in the invention signifies mixtures of o-,p-,m-cresols, knownas cresylic acid, and mixtures of cresylic acid with phenol. Theresulting mixture is heated to form a solution. Water of reaction of thealiphatically unsaturated carbonyl compound and the organic diamine iscontinuously separated as a hydrocarbon-water azeotrope. The resultingmixture is allowed to cool. The resulting reaction mixture can beemployed to treat substrates to provide polyimide films by solventevaporation and heat cure. If desired, the polymeric reaction producthereinafter referred to as prepolymer" or aliphatically unsaturatedimide prepolymer can be recovered by pouring the reaction mixture into amedium such as water, methanol, etc.

In forming the reaction mixture, the order of addition of the variousingredients is not critical. There can be employed from 0.5 to 2 molesof organic diamine, and preferably from 0.6 to 1.2 moles, per mole ofthe aliphatically unsaturated dicarbonyl compound.

in the reaction mixture the proportions of solids and solvent can varywidely. Preferably, solids can be employed at about 20 to 50 percent byweight of total mixture. Effective results can be achieved with aslittle as 10 percent by weight of phenolic solvent, while the amount ofhydrocarbon solvent which can be employed should be at least sufficientto effect the separation of water of reaction of the organic diamine andthe aliphatically unsaturated dicarbonyl compound. Hydrocarbon solventswhich can be employed preferably have a boiling point in the range offrom to C. and include, for example, xylene, toluene, commercialhydrocarbon fractions, etc.

Effective results can be achieved at temperatures in the range ofbetween 80 to 200 C. and preferably between 140 to C. Depending uponsuch factors as the reactants,

degree of agitation, temperature, etc., the formation of the prepolymercan be achieved in 2 hours or less.

Recovery of the prepolymer can be effected by allowing the reactionmixture to cool to room temperature and pouring the reaction mixtureinto a precipitating medium such as excess water, a monohydric aliphaticalcohol such as methanol, or other material employed in accordance withstandard techniques. Filtration of the resulting mixture, followed bydrying of the product will provide the prepolymer suitable for blendingwith other materials, such as filler, etc. If desired, the reactionsolution can be employed directly without effecting the precipitation ofthe prepolymer to cast prepolymer film or to treat substrates byeffecting the seaparation of the prepolymer through solvent evaporation.

The prepolymers of the present invention can be blended with variousaliphatically unsaturated organic materials, such as aliphaticallyunsaturated organic monomers, and certain aliphatically unsaturatedorganic polymers as well as organic polymers free of aliphaticunsaturation. Blends of the prepolymers and the aforementioned organicmonomers or polymers can be made over wide proportions by weight.Experience has shown that there should be employed at least about 25percent by weight ofprepolymer in the blend to provide for curedproducts having improved characteristics.

Among the various uses to which the aliphatically unsaturated imideprepolymers of the present invention can be employed are, for example tomake laminating compounds, solvent resistant varnishes, moldingcompounds, coating compositions, etc., depending upon the proportions ofthe prepolymers and the organic polymer or monomer utilized in theblend.

Some of the aliphatically unsaturated monomers which can be blended withthe prepolymers of the present invention are, for example styrene,bismaleimide, N-phenylmaleimide, divinylbenzene, triallylcyanurate,triallyltrimellitate. Among the organic polymers which can be employedin combination with the prepolymers of the present invention are, forexample, polyvinylchloride, polyethylene, polypropylene, polysulfones,polystyrenes, polyurethane, organopolysiloxanes, polyesters, etc., andblends thereof.

Cure of the aliphatically unsaturated imide prepolymer of the presentinvention or blend thereof within the aforementioned organic monomers ofpolymers or combination thereof can be effected thermally or by the useof conventional free radical initiators. Temperatures of from 50 to 3000C. can be employed while 100 to 200 C. have sometimes been found to bemore desirable. Acceleration of the cure of the aliphaticallyunsaturated prepolymer or blend thereof can be achieved with organicperoxides such as dicumyl peroxide, benzoyl peroxide, tertiarybutylperbenzoate, tertiary alkylperoxy carbonate, azodicarboamide,2,5-dimethyl-2,5-bis- (tertiarybutylperoxyhexane), etc. The peroxidescan be employed from about 0.01 percent to about 5 percent by weightbased on the total weight of the blend. In addition, the aliphaticallyunsaturated imide free polymer or blend thereof can be cured with heator irradiation with high energy electrons, x-rays, ultraviolet light,etc., in addition to the aforementioned free radical initiators.

In addition to the aforementioned aliphatically unsaturated monomers,and organic polymers, the aliphatically unsaturated imide prepolymers ofthe present invention can be blended with from 0 to 200 parts of fillerper 100 parts of the prepolymer. Included by the fillers which can beemployed are, for example, clay, ground quartz, silica, sand, carbonblack, glass fibers, glass beads, carbon fiber, asbestos, etc. lnaddition, other ingredients such as solvents are from 60 to 90 percentby weight of the resulting curable compositions also can be employedsuch as N-methylpyrrolidone, dimethylacetamide, toluene,ethylenechloride, as well as plasticizers such as dialkylphthalate, etc.

1n order that those skilled in the art will be better able to practicethe invention, the following examples are given by way of illustrationand not by way oflimitation.

EXAMPLE 1 A mixture of98.06 parts ofmaleic anhydride, 99.13 parts ofp,p'-methy1enedianiline, 789.8 parts of distilled cresol and about partsof xylene was stirred and heated to a temperature of 100 C. to produce ahomogeneous solution. The mixture was then heated to a temperature ofabout 150 C. and a xylene-water azeotrope started to separate. Heatingof the mixture was continued to a temperature of about 170 C. to effectthe separation of about 93.3 percent of theoretical water of reaction ofthe maleic anhydride and the p,p'- methylenedianiline. The mixture wasthen allowed to cool to room temperature. It was poured slowly intoexcess methanol to affect the precipitation of product. The product wasdried at 50 C. under reduced pressure for a period of about 5 hours.There was obtained a quantitative yield of a cream colored product.Based on method of preparation, the product was a low molecular weightpolyimide having about three or four chemically combined imide unitsresulting from the reaction of maleic anhydride andp,p-methy1enedianiline.

The above prepolymer is molded at a temperature of 325 C. to produce aflexible film having a tensile strength of about 5,000 psi.

EXAMPLE 2 In accordance with the procedure of Example 1, a mixture ofmaleic anhydride, p,p-methylenedianiline, cresol, and xylene was madeutilizing an equal molar amount of maleic anhydride andp,p'-methylenedianiline. The mixture was stirred and heated until aclear solution was obtained at C. At 192 C., a xylene-water a azeotropebegan to distill over. After an hour of heating at a temperature to213C, 95.6 percent of the theoretical water was separated. The solutionwas then allowed to cool to room temperature. Based on method ofpreparation, there was obtained an olefinically unsaturated polyimideprepolymer. A film was cast from the solution on a glass substrate. Thefilm was cured by heating it at C. for 1 hour and 200 C. for 1 hour. Thefilm was found to have valuable dielectric and insulatingcharacteristics.

A portion of the above solution was slowly added to excess methanolresulting in the precipitation of a yellow-colored solid. The solid wasdried at 100 C./8 mm for 5 hours. A portion of the yellow solid wasmolded at a temperature of 300 C. for 30 minutes at a pressure of 5,000psi. There was obtained a test bar having superior shear modulus. Theprepolymer is suitable for making bearings and automotive partsrequiring high temperature stability.

The above procedure was repeated except that a solution was madeutilizing 2 moles of p,p'-methylenedianiline, per mole of maleicanhydride. The mixture of maleic anhydride, p,p-methylenedianiline,cresol and xylene was stirred and heated until a solution was formed at140 C. Heating was continued until a xylene-water azeotrope began todistill from the solution at 170 C. The mixture was heated for anadditional hour at a temperature to 210 C. resulting in the separationof 95.6 percent of the theoretical water of reaction. The mixture waspoured into methanol to effect the precipitation of a quantitative yieldof a cream colored solid. The solid began to soften at 132 C. and wassufficiently fluid at 166 C. to allow incorporation of a reinforcingfiller. Based on method of preparation, the solid was an amineterminated polyimide prepolymer of about 3 or 4 chemically combinedunits of the reaction product of a p,p'-methylenediani1ine and maleicanhyride.

A blend of 30 parts of the above prepolymer and 70 parts of glass fiberis made in a Waring blender. There is added 0.1 percent by weight ofdicumyl peroxide. The resulting blend is molded at C under a pressure of5,000 psi to a test bar exhibiting superior shear modulus.

EXAMPLE 3 A mixture of 251.2 parts of distilled cresol, about 25 partsof xylene, 24.78 parts of p,p-methylenedianiline and 29.02

parts of fumaric acid was heated and stirred until a solution was formedat 150 C. At 170 C., a xylene-water azeotrope began to distill over andthe mixture was heated to 190 C. for an additional hour. This resultedin the separation of the theoretical amount of water of reaction betweenthe dicarboxylic acid and the diamine. The mixture was then allowed tocool to room temperature and a cloudy heterogeneous mixture wasobtained. A cream colored solid was obtained by pouring the mixture intomethanol which was dried at 50C under reduced pressure for about 5hours. There was obtained about an 88 percent yield of product. Theproduct softened at 205 C and flowed at 290 C.

A blend of 30 parts of the above product and 70 parts of glass fibers ismilled. There is then added 0.1 part of benzoylperoxide to the resultingmixture. The mixture is then molded at 265 C. under a pressure of 5,000psi for 15 minutes to produce a test bar. The product is found to beflexible and shows superior shear modulus indicating that it is usefulas a laminating and molding compound.

EXAMPLE 4 A mixture of 229 parts of distilled cresol, 25 parts xylene,24.78 parts of p,p'-methylenedianiline and 32.53 parts of itaconic acidwas heated to a temperature of 120 C. resulting in the formation of asolution. A water-xylene azeotrope began to separate at 160 C. Uponcontinued heating to a temperature of 190 C. for a period of about anhour, there was effected about 100 percent separation of water ofreaction of the itaconic acid and the p,p-methylenedianiline. Thesolution was then allowed to cool to room temperature and added to anexcess of methanol. A white solid precipitated. 1t was collected anddried at 50 C. under reduced pressure for 5 hours. Based on weight ofstarting reactants, there was obtained about an 85 percent yield of apolyimide prepolymer having a softening point of about 240-250 C.

A test bar is made from the prepolymer in accordance with the method ofExample 1. It is found to be flexible and suitable for makingtemperature resistant bearings.

EXAMPLE 5 A mixture of 9.8 parts of aniline, 34.7 parts ofp,pmethylenedianiline, 175 parts of cresol and 25 parts of xylene wasadded to 34.3 parts of maleic anhydride. The resulting mixture wasslowly heated to a temperature of 180 C. and refluxed for 1 hour. Duringthe course of heating, a solution of the various ingredients wasobtained and water of reaction was separated. After a theoretical amountof water had been collected, the mixture was allowed to cool to roomtemperature. It was poured into excess methanol to produce a yellowprecipitate. After the precipitate was dried under 14 mm/l-lg pressurefor 16 hours at about 25 C, there was obtained a substantial yield ofproduct based on weight of starting material. The product softened atabout 120 C. Based on method of preparation, the product was a polyimideprepolymer resulting from the reaction of p,p'-methylenedianiline,aniline, and maleic anhydride and averaging about three or fourchemically combined reaction product units.

A blend is made of 30 parts of the above prepolymer and 70 parts of 3/16 inch glass fibers. There is added to the resulting blend, 0.3 partsof dicumyl peroxide. The mixture is milled and moldedat 165 C. for 10minutes at 5,000 psi. The resulting molded bar has a modulus of about2X10 psi.

EXAMPLE 6 A mixture was made of 15.12 parts of m-phenylenediamine, 13.7parts of maleic anhydride, 75 parts of distilled cresol and 75 parts ofxylene. The mixture was heated with stirring to produce a solution at 60C. At 140 C., a xylene-water azeotrope began to distill over. Heating ofthe mixture was continued to 160 C. resulting in the separation of 100percent of the theoretical water of reaction of the maleic anhydride andthe m-phenylenediamine. The mixture was then allowed to cool to roomtemperature. A prepolymer was precipitated from the mixture by slowlyadding it to excess methanol. A 93 percent yield of a yellow solid wasobtained by filtering the mixture. It was dried at 50 C. under reducedpressure for 5 hours. The product had a softening point of 350 C. Basedon method of preparation, the product was a prepolymer having an averageof about three or four chemically combined intercondensation unitsresulting from the reaction of maleic anhydride and m-phenylenediamine.

A film was cast from a 30 percent solids solution of the aboveprepolymer in N,N-dimethylformamide. The film was cured by heating it toa temperature of between 250 C. over a period of about 1 hour. The curedproduct was flexible indicating that it would be suitable in a varietyof coating applications such as a wire enamel.

EXAMPLE 7 A mixture was stirred and heated consisting of 46.5 parts ofhexamethylenediamine, 27.4 parts of maleic anhydride, parts of distilledcresol and 150 parts of xylene. A solution of the aforementionedingredients was obtained with stirring at a temperature of about 70 C. Axylene-water azeotrope began to separate from the mixture at atemperature of 150 C. Heating was continued and at a temperature of 157C. over 97 percent of the theoretical water was recovered. The mixturewas then allowed to cool to room temperature. A film was cast from theresulting solution onto a glass substrate. It was cured at 100 C. for 1hour and 200 C. for an additional hour. The film was found to beflexible and it had a cut-through temperature of 395 C. in measuring thecutthrough, the film was placed between 50 mil conducting wires under a1,000 gram load in accordance with the method described in Precopio etal. US. Pat. No. 2,936,296 assigned to the same assignee as the presentinvention. The film was suitable as a wire enamel and other insulatingapplications requiring the services of a high temperature resistantmaterial.

EXAMPLE 8 A mixture of 21.6 parts of m-phenylenediamine, 13.7 parts ofmaleic anhydride, 75 parts of distilled cresol and 75 parts of xylenewas charged to a reaction vessel. The mixture was stirred and heated. At60 C., a solution of the various ingredients was obtained. Heating ofthe mixture was continued to 140 C. resulting in the separation of axylene-water azeotrope. The theoretical amount of water of reactionseparated when the mixture was heated with stirring to 160 C. Themixture was then allowed to cool to room temperature. It was pouredslowly into methanol to effect precipitation of reaction product. Afterit had been collected and dried for 5 hours at 50 C. under reducedpressure, there was recovered a 95.8 percent yield of a yellow solid.The product had a softening point of about 256259 C. Based on method ofpreparation and its infrared spectrum, the product was a polyimideprepolymer having an average of three or four chemically combinedreaction product units of maleic anhydride and mphenylenediamine.

EXAMPLE 9 The procedure of Example 9 was repeated, except that there wasemployed in the reaction mixture 39.2 parts of p,pmethylenedianiline,27.4 parts of maleic anhydride, 150 parts of distilled cresol and 150parts of xylene. A solution of the in- .gredients was obtained at atemperature of about 60 C. A

xylene-water azeotrope started to separate at a temperature of about 140C. After heating the mixture to C., 100 pertrum, the product was aprepolymer having greater than two chemically combined units resultingfrom the intercondensation of p,p'-methylenedianiline and maleicanhydride.

EXAMPLE A mixture of 79.2 parts of p,p'-methylenedianiline, 20.6 partsof maleic anhydride, 11.4 parts of endomethylene tetrahydrophthalicanhydride, 250 parts of cresol and 50 parts of toluene is heated andstirred for 1 hour in accordance with the above-described procedure. Asolution of the aforesaid mixture is formed at a temperature of about 60C. A watertoluene azeotrope begins to separate from the mixture at atemperature of about 115 C. At a temperature of l55 C., the theoreticalwater of reaction of the organodiamine and unsaturated anhydride iscollected. A prepolymer is precipitated by pouring the mixture intoexcess methanol after it is allowed to cool. There is obtained aquantitative yield of product.

A solution is made by mixing 10 parts of the prepolymer and 10 parts ofdimethylformamide. The solution is employed to coat a 2X2 inch glasscloth by immersing the cloth into the solution. The cloth is dried at120 C. for 8 minutes. After preparing of such treated cloths, they aresubjected to a pressure of 200 psi at room temperature and then slowlyheated to 200 C. for 1 hour. There is obtained a void-free laminatewhich is useful as an electrical circuit board.

EXAMPLE 11 A mixture of 99.14 parts of methylenedianiline, 39.25 partsof maleic anhydride, 315.6 parts of cresol and 100 parts of toluene isheated at l00-l50 C. for 1 hour. During this period, the theoreticalwater of reaction is separated.

The mixture is cooled to 50 C. and 32.22 parts ofbenzophenonetetracarboxylic acid dianhydride is added. A clear viscoussolution is obtained on cooling. A film is cast from the solution ontoan aluminum substrate. The film is heated for 1 hour at a temperaturebetween l00-250 C. There is obtained a cured polyimide film which isfound to be flexible and useful as an insulating material.

Although the above examples illustrate only a few of the very manyvariables which can be employed in the practice of the presentinvention, it should be understood that the present invention isdirected to a method for making a much broader class of polyimideprepolymers and to the products produced thereby utilizing the organicdiamines shown by formula (I) or mixtures of such materials with organicmonoamines as previously defined, in combination with aliphaticallyunsaturated organic anhydrides, dicarboxylic acids, or mixtures thereof,employing the solvents and the conditions defined above.

We claim:

I. A method which comprises, (1) heating at a temperature in the rangeof from to 200 C. a mixture comprising (A) from 0.5 to 2 moles ofhydrocarbon diamine consisting essentially of arylene hydrocarbondiamine, per mole of (B) aliphatically unsaturated hydrocarbondicarboxylic acid anhydride in the presence of (C) an inert hydrocarbonsolvent, and (D) an inert phenolic solvent, (2) separating a hydrocarbonsolvent-water azeotrope from the mixture of l and (3) recovering thecurable condensation product of (A) and (B) from the resulting mixtureof( l 2. A method in accordance with claim 1, where the arylenehydrocarbon diamine is 4,4'-diaminodiphenylmethane.

3. A method in accordance with claim I, where the aliphaticallyunsaturated organic anhydride is maleic anhydride.

4. A method in accordance with claim 1, where the aliphaticallyunsaturated hydrocarbon anhydride is a member selected from the groupconsisting of a mixture of maleic anhydride and endomethylenetetrahydrophthalic anhydride, a mixture of maleic anhydride andtetrahydrophthalic anhydride, and a mixture of maleic anhydride and upto 10 mole percent, based on the moles of hydrocarbon anhydride in saidmixture of hydrocarbon dianhyd ride.

5. A method in accordance with claim 1, where the arylene hydrocarbondiamine is m-phenylenediamine.

6. A method in accordance with claim 1, where the arylene hydrocarbondiamine is a mixture of an arylene hydrocarbon diamine and an arylenehydrocarbon monoamine.

2. A method in accordance with claim 1, where the arylene hydrocarbondiamine is 4,4''-diaminodiphenylmethane.
 3. A method in accordance withclaim 1, where the aliphatically unsaturated organic anhydride is maleicanhydride.
 4. A method in accordance with claim 1, where thealiphatically unsaturated hydrocarbon anhydride is a member selectedfrom the group consisting of a mixture of maleic anhydride andendomethylene tetrahydrophthalic anhydride, a mixture of maleicanhydride and tetrahydrophthalic anhydride, and a mixture of maleicanhydride and up to 10 mole percent, based on the moles of hydrocarbonanhydride in said mixture of hydrocarbon dianhydride.
 5. A method inaccordance with claim 1, where the arylene hydrocarbon diamine ism-phenylenediamine.
 6. A method in accordance with claim 1, where thearylene hydrocarbon diamine is a mixture of an arylene hydrocarbondiamine and an arylene hydrocarbon monoamine.